351 vs 454

[DCJ]

I am looking at older Sunsports and Mariahs and have noticed PCM Ford 351 engines most common although some do have the PCM GM 454 engines. How do these two engines compare in terms of performance, gas usage and reliability? Is there any reason to avoid either engine from a particular model year?

[csuggs]

Welcome to the forum DCJ. The big block boats came with about 330hp and the more common 351W had 240hp. Of course the 454 will suck a lot more gas especially at higher rpms, but it will also offer a littler more torque and top end if set up right. I think either motor is good and reliable so if you don't care about buying gas, I would make my choice based on the boat and condition of the boat, and not the motor. As for me, I like the 351. It has plenty of torque for anything that I want to do and is still pretty easy on gas at wakeboard speeds. FYI - I think the 454 boats were originally offered for barefooting - better hole-shot and higher top-end.

[dshaff24]

Ive had a few different selections of motors from different boats and I will say that the 351 in my oldest boat Ive ever owned gets the most Time to fuel consumption, Also might be because this is the first boat that Ive owned thats not a Speed Boat to, But I will say the 351 is a super smooth and quiet motor compared to some 350 mags and 454 mags that ive owned, Im personally a chevy man but This was my first ford and I am very happy with it!

[sybrmike]

Welcome aboard. I'm sure you'll find lots of help here. The "standard" for older tournament style inboards are small block chevys & fords and still are today. They weren't neccessarily built for high rpm or hp, but torque and longevity better suited for boating - when's the last time you mashed the throttle in your car while pulling a load & then kept it at 1/2 to 3/4 for awhile and then repeated this all day? Plenty of power for most needs & not too bad on the gas.

The added hp and torque of a big block can help with bigger loads like barefoot deep water starts or a bigger hull (like the 23' Saltare), but at the price of gas consumption. Sure, you can get a comparable 330 hp out of a small block (like the newer fuel injected, knock sensored, computer controlled, roller boat engines of today), but to keep them durable and torquey "back then" - there's no substitute for displacement.

These hulls were'nt built for speed (usually low 40's mph max), but rather to plane quickly, track straight, & throw a small wake. For those purposes, a small block is more than adequate. The added torque of a big block might be helpful if you're gonna really sack it out for boarding.

[jet]

DCJ. All you need is 351 and a big 4-Blade. Remember...$4 a gallon is coming back! Jet

[beast 496]

Ok, here is the situation I had. On our Beast, the original 454 is so enemic on HP 330. I just had to have alot more. Swapped in a 496 HO MPI. Better fuel economy and alot more power, 425HP. Changed prop to 13X18 SST three blade pulls even at 5,000 rpm at WOT. At 30 MPH 2,100 rpm getting 3 mpg. Basically turning large pitch prop which moves more water at a lower rpm equalls better fuel economy. Plus having the MPI equalls better drivability, easy starting every time. The Velvet drive tranny so far is holding up. Al